Steve did a great job of explaining the difference between var vs. vart.  As Steve said, “var” is the word “where” in a static sense and “vart” is “to where.”  As you continue learning Swedish, this will become more and more natural.  But as this becomes more natural, there is a second aspect of questions to keep in mind.  Platsadverbials.  Adverbials that indicate place.

As mentioned, var is a static sense of where, while vart is a directional to where.  This distinction carries over when using platsadverbials.  Below is a list to get you started:

And finally, a few sentences to demonstrate the difference:

–Vart går du efter lunch? (Where do you go to after lunch?)
-Jag går hem. (I go home.)

–Var äter du på kvällen? (Where do you eat in the evenings?)
-Jag äter hemma. (I eat at home.)

–Var är min bok? (Where is my book?)
-Den ligger här på bordet.  (It is lying here on the table.)

–Vart ska de åka nu? (To where are they traveling now?)
-De ska komma hit! (They are coming [to] here!)

The sentences above give a simple demonstration of the differences in uses between var and vart. You’ll notice that in each case, the var or vart corresponds with the platsadverbial.  This agreement is key to mastering the use of var and vart and the corresponding platsadverbials.

Good luck!